The present invention relates generally to the field of dispensing pumps for fluids and more particularly toward pumps of this type that have a child proof lockable feature.
There are classes of fluid dispensers for both consumer and industrial use in which a reciprocating pump element is threaded into a housing for locking in a retracted position for storage and shipping. A number of proposals have been made to introduce a locking childproof function in dispensers of this type.
U.S. Pat. No. 5,405,057 is an example of such a device. A reciprocating plunger is required to be rotated into alignment with recesses and notches to permit reciprocation. The problem with this type of device is that inadvertent manipulation by a child could bring the plunger into alignment so as to permit reciprocation.
The present invention provides an effective and novel alternative to the childproof design mentioned above. It involves the incorporation of various locking mechanisms that require displacement of an operator-manipulated component in a direction other than the direction required to unthread the plunger for pumping movement. This displacement must be done simultaneously with the unthreading movement to minimize, if not eliminate, the possibility of unauthorized plunger pumping.